The present study was attempted to test whether the treatment of spermatogonial cells with procarbazine induces reciprocal translocations or sperm abnormalities. No translocations were observed in 840 spermatocytes of control animals or 680 cells of animals treated with 400 mg/kg. Only one translocation was observed among 1000 spermatocytes of animals with 100 mg/kg. A significant increase in the proportion of sperm with abnormal heads was observed at 400 mg/kg but not at 100 mg/kg.